1. Technical Field
The present invention relates to devices for the treatment of venous insufficiency and lymphedema.
2. Background Art
A healthy vein contains valves that open and close to assist the return of blood to the heart. Venous insufficiency refers to damaged or diseased valves that can result in a backward flow of blood, a condition known as venous reflux. This reflux causes blood to pool, often in the lower legs, and can lead to symptoms of pain and swelling. Chronic venous insufficiency (CVI) is a long-term, persistent state of venous reflux and associated symptoms. Advanced stages can lead to inflammation, deep vein thrombosis (DVTs, known as blood clots), ulcers and limb amputation. These symptoms can be unbearable and affect daily activities. Varicose veins are often a precursor or symptom of CVI. Valves become damaged or diseased for many reasons, including obesity, heredity, prolonged standing and inactivity. There are currently an estimated 24 million people in the United States with varicose veins. An estimated 6 million individuals in the United States have severe symptoms of CVI ranging from skin changes to ulcerations. Annual treatment costs of venous ulcers in the United States are estimated to be $3 billion with a loss of 2 million work days as a result.
Lymphedema is a condition where swelling occurs due to an accumulation of lymphatic fluid often in the legs and arms that is unable to drain back into the blood circulation because of a compromised lymphatic system. As the lymph fluid pools a high concentration of bacteria may form and the swollen area becomes more susceptible to infection. Patients with lymphedema experience pain and are at risk of severe infection. Similar to venous insufficiency, lymphedema occurs for a variety of reasons including, obesity, heredity, and inactivity. Lymphedema is also known to occur after certain cancer surgeries, such as breast cancer, where the lymph nodes are disrupted due to radiation treatments. It is estimated that 3 to 5 million people in the United States experience lymphedema.
Even with the high incidence of venous insufficiency and lymphedema, the existing treatment options available are ineffective and outdated, especially given the technological advances in electronics and hardware within the last decade. In addition, chronic conditions of these disease states mean that the patient will need life-long therapies to treat the symptoms. Existing treatments to reduce the swelling associated with venous insufficiency and lymphedema are often difficult to apply, uncomfortable, and/or render the user immobile. The result is that the user often abandons treatment and the swelling persists. Existing treatments include, but are not limited to, elastic compression stockings, inelastic compression bandages, and external compression pumps. Elastic compression stockings have the complication in that they are very difficult for the user to pull them over the swollen area. The stocking is such a tight fit to begin with that the user struggles to pre-compress the swollen area so that it can slide into the stocking. Further, in hot environments, the stockings are insufferable. Often the patients are non-compliant with elastic compression stocking treatments. Inelastic compression bandages are wraps that are similar to wearing a cast and are normally applied by a certified technician. The user must go to a particular venue or clinic where the wraps are applied. The user's mobility is limited by the wraps and they are unable to bathe the wrapped area during treatment. Often the skin becomes rough, eczema forms and the area becomes odorous. The treatment is approximately a 2-week cycle that includes removing and rewrapping the swollen area. External compression pumps require a cumbersome pumping unit and a power outlet to inflate a sleeve or boot that is placed over the swollen area. The treatments can be done at home; however, an approximate treatment regiment requires one-hour sessions 5 days a week for 35 sessions. These units require that the user be immobile during the treatment period.
U.S. Patent Application Publication No. 2008/0071135 to Shaknovich discloses a treatment strategy for treatment of elevated pressure in a body conduit, such as a pulmonary vein, with a prosthetic partitioning device that permits coaxial attachment to the body conduit, e.g. the pulmonary vein, as well as delivery systems, and strategies for use thereof. A control device configured to transmit signals to the prosthetic device to effectuate the repetitive transition between a first, less restricted flow configuration and a second, restricted flow configuration is described. A sensor device can be provided for monitoring physiological parameters of the patient, and can provide signals to the control device for effectuating the transition between the first and second configuration. The prosthetic partitioning device can include one or more inflatable members (shown at 20 in the figures in the '135 application) that are supplied with gas or fluid by an implantable pump via a supply line (shown at 26 in the '135 application). A control device (shown at 14 in the '135 application) controls the configuration of the prosthetic partitioning device between less and more restriction of flow.
U.S. Patent Application Publication No. 2009/0248142 to Perkins, et al. discloses methods and systems for improving the competency of a venous valve wherein one or more compressor(s) (e.g., space occupying material(s) or implantable device(s)) is/are delivered to one or more location(s) adjacent to a venous valve to compress the venous valve in a manner that causes one or both leaflets of the valve to move toward the other, thereby improving closure or coaptation of the valve leaflets. The compressor(s) can be delivered by an open surgical approach, by a direct percutaneous approach or by a transluminal catheter-based approach. The compressor can be an implantable, inflatable member filled with solid, liquid, gaseous, or gelatinous material. The device is inserted in a contracted state and once in place is activated to be in an expanded state. However, once expanded, the compressor does not again retract, and there is no control to manipulate the configuration of the compressor.
It is important to note that the prior art prosthetic devices are required to be attached directly to the veins necessitating major invasive surgery in order for the devices to be implanted. For example, the motivation of the '135 application to Shaknovich is for the prosthetic to be clamped to the pulmonary vein. There remains a need for a prosthetic device that does not require direct access to the veins in order to generate therapeutic compression and that is a minimally invasive surgical procedure. There remains a need for a treatment of venous insufficiency and lymphedema that is easy to use, easier to implant, and effective that overcomes the deficiencies of the prior art.